This invention relates to hydroxyl-terminated polybutadiene compositions, curable compositions comprising such hydroxyl-terminated polybutadienes, resin products made by reacting such hydroxyl-terminated polybutadienes with polyisocyantes, epoxy resins, anhydrides, amines, or phenolics, and cured polymers based on such formulations such as polyurethanes.
Prior hydroxyl-terminated polybutadienes prepared by radical polymerization, such as commercially available ones sold under the designations Poly bd R45HTLO or Liquiflex P, contain a large percentage of oligomers and polymers with branched microstructures and more than 2.0 hydroxyl functionalities per molecule, with an average functionality of such polybutadienes is about 2.4-2.6 hydroxyl groups per polymer molecule. Polyurethane formulations prepared from such branched hydroxyl-terminated polybutadienes reacted with polyisocyanates exhibit low tensile and tear strength properties.
Prior hydroxyl-terminated polybutadienes derived from anionic polymerization, such as Krasol® LBH 2000, 3000 and 5000, and the Nisso-G series have a non-branched structure and a maximum of 2.0 hydroxyl functionalities per chain, typically 1.8-1.9 hydroxyl groups per polymer chain. Such non-branched hydroxyl-terminated polybutadienes have been used in the prior art for reaction with organic polyisocyanates, to form polyurethanes or urethane-terminated prepolymers.
It has been a longstanding objective of those skilled in this art to form polyurethanes with improved and unique combination of properties, and to form prepolymers with lower viscosity and with improved storage stability thereof.
It has also been an objective in this art to improve the thermoplasticity and modulus of the chain extended cured resins of this type.